Fast Overvoltage Detection Circuit for High Speed Switches
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing over-voltage protection systems for high-speed or load switches are inefficient in detecting and responding to surge events, leading to potential damage due to continuous current consumption and inadequate protection during normal conditions.
Innovation Solution
A protection circuit with a pad, multiple circuit branches, and a controller that enables a comparator only during surge events, using extended drain transistors and diode-connected transistors to detect and respond to over-voltage conditions, shutting down switches to prevent damage while minimizing current consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the protection circuit continuously monitors for surge events, then the detection reliability is improved, but the current consumption increases during normal operation
Solution Approach 1:
The protection circuit dynamically switches between active monitoring mode and low-power standby mode based on the operational state of the switch. When the switch is OFF, the monitoring circuit is disabled to minimize current consumption. When the switch is ON, the monitoring circuit activates to provide surge detection, thus adapting the system's energy consumption to its actual protective needs.
Solution Approach 2:
The protection circuit employs periodic sampling of the switch state to determine when to activate the surge monitoring function. Instead of continuous monitoring, the system periodically checks the switch state and activates monitoring only when necessary, reducing overall current consumption while maintaining adequate protection coverage.
2Speed
If the comparator is always enabled for fast surge detection, then the response speed is improved, but the current consumption increases
Solution Approach 1:
The comparator is enabled only during periodic intervals when the switch is detected to be in the ON state. During these intervals, the comparator provides fast surge detection. Between these intervals, when the switch is OFF, the comparator remains disabled to conserve current, thus achieving periodic high-speed detection with reduced overall power consumption.
Solution Approach 2:
The comparator's operational state is dynamically controlled based on real-time switch status. The system transitions the comparator between enabled and disabled states according to whether the switch is ON or OFF, optimizing the balance between detection speed and power consumption by activating the high-speed comparator only when protective action is actually needed.
3Use of energy by moving object
If the protection circuit remains in standby mode to save power, then the current consumption is reduced, but the response time to surge events increases
Solution Approach 1:
The system performs preliminary activation of the monitoring circuit based on predictive switching patterns. When the controller intends to turn the switch ON or when the switch transitions to ON state, the monitoring circuit is proactively enabled in advance, ensuring that surge detection is already active before potential surge events occur, thus minimizing response time without requiring continuous monitoring.
Solution Approach 2:
The protection circuit dynamically transitions between standby and active monitoring states based on switch state changes. Upon detecting that the switch is turning ON or has turned ON, the system rapidly transitions from low-power standby to active monitoring mode, minimizing the time spent in each state while optimizing the balance between power consumption and response time.
4Use of energy by moving object
If the protection circuit is activated only when the switch is ON, then the current consumption is minimized, but the protection coverage is reduced
Solution Approach 1:
The protection circuit is activated in advance based on the controller's switching commands or transition detection. When the controller signals an intended switch ON state or when the switch begins transitioning to ON, the protection circuit proactively activates, ensuring coverage is already in place before the switch is fully conducting, thus maintaining protection coverage while minimizing activation duration and current consumption.
Solution Approach 2:
The system rapidly transitions the protection circuit through activation and deactivation states synchronized with switch state changes. By rushing through the activation process immediately upon detecting switch ON conditions and quickly deactivating when the switch turns OFF, the system minimizes the duration of high current consumption while ensuring protection is present during the critical conducting period of the switch.
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A protection circuit including a pad configured to input an external voltage from a connector, a first circuit branch connected to the pad and configured to receive a fast ramp-up surge at the pad, a second circuit branch connected to the pad and configured to receive a ramp-up surge at the pad, a third circuit branch connected to the pad and configured to output a surge detection signal when a surge voltage is received at the pad, an enabling transistor connected between the second circuit branch and the third circuit branch, at least one switch to be protected, and a controller configured to control components of the second circuit branch and third circuit branch of the protection circuit based on an on-state of the at least one switch to be protected.